Lord Capulet was Juliet's father. Along with his family (excluding Juliet), he was killed in Lord Montague's coup d'état fourteen years before the story starts, as a part of Montague's scheme to take over Neo Verona and achieve revenge on the whole Capulet clan for the suffering and pain he and his mother went through for them. Although Lord Capulet was only seen at the beginning of the series before he was murdered by Lord Montague, he was mentioned several times by other characters.

He was depicted as being a kind, wise and fair ruler over Neo Verona, before the murder of his family. In the original play Lord Capulet and his wife live through the entire play; while present, he appears as a loving father to Juliet, though he also acts stubborn and controlling. At the end of the play, he makes peace with Montague after the death of his daughter and son-in-law.

(Source: Wikipedia)